Fluoropolymers have found widespread use in demanding applications where their non-stick properties, good thermal and chemical resistance, toughness and abrasion resistance are being used to advantage, such as in coatings.
The present invention provides blends of (a) amorphous fluoropolymers with (b) certain cross-linkable terpolymers derived from fluorine-containing acrylic monomers with non-fluorinated acrylic monomers. These blends can be cured by application of heat to form semi-IPNs (interpenetrating networks) of the cured terpolymer which "trap" the amorphous fluoropolymer component. The cured blends remain amorphous, and they are optically clear. Those which are based on amorphous fluoropolymers containing only carbon and fluorine, and possibly hydrogen and/or oxygen, also have low refractive indexes. Being soluble in specific organic solvents, solutions of the uncured blends can be used to make coatings and to cast films, which are cross-linkable. These coatings are optically clear, robust and strongly adherent to substrates, including glass, polymer films, metals and crystal substrates.
These new polymer blends fill a need for coating materials which have the superior properties of fluoropolymers--such as low refractive index and surface energy, good thermal and chemical resistance--and which at the same time have strong adhesion, flexibility, toughness, and abrasion resistance. The polymer blends of the present invention combine these properties.